If you need an easy way to convert a decimal julian day to an unix timestamp you can use:
$unixTimeStamp = ($julianDay - 2440587.5) * 86400;
2440587.5 is the julian day at 1/1/1970 0:00 UTC
86400 is the number of seconds in a day
jdtounix
(PHP 4, PHP 5, PHP 7, PHP 8)
jdtounix — Convertit un jour Julien en timestamp UNIX
Description
Retourne un timestamp UNIX correspondant au jour Julien
julian_day ou false si julian_day
n'est pas dans l'intervalle autorisé. Le temps retourné est UTC.
Liste de paramètres
-
julian_day -
Le nombre de jours Julien, compris entre
2440588et106751993607888sur les systèmes 64bit, ou compris entre2440588et2465443sur les systèmes 32bit.
Valeurs de retour
Le timestamp unix pour le début (minuit, pas midi) du jour Julien donné.
Erreurs / Exceptions
Si julian_day est hors de l'intervalle autorisé,
une ValueError est lancé.
Historique
| Version | Description |
|---|---|
| 8.0.0 |
Cette fonction ne retourne désormais plus false en cas d'échec,
mais lève une ValueError à la place.
|
| 7.3.24, 7.4.12 |
La limite supérieure du paramètre julian_day a été
étendue. Avant, elle était de 2465342 suivant
l'architecture.
|
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User Contributed Notes 5 notes
fabio at llgp dot org ¶
18 years ago
Anonymous ¶
19 years ago
Warning: the calender functions involving julian day operations seem to ignore the decimal part of the julian day count.
This means that the returned date is wrong 50% of the time, since a julian day starts at decimal .5 . Take care!!
seb at carbonauts dot com ¶
21 years ago
Remember that unixtojd() assumes your timestamp is in GMT, but jdtounix() returns a timestamp in localtime.
This fooled me a few times.
So if you have:
$timestamp1 = time();
$timestamp2 = jdtounix(unixtojd($timestamp1));
Unless your localtime is the same as GMT, $timestamp1 will not equal $timestamp2.
pipian at pipian dot com ¶
21 years ago
Remember that UNIX timestamps indicate a number of seconds from midnight of January 1, 1970 on the Gregorian calendar, not the Julian Calendar.
Saeed Hubaishan ¶
10 years ago
unixtojd() assumes that your timestamp is in GMT, but jdtounix() returns a timestamp in localtime.
so
<?php
$d1=jdtogregorian(unixtojd(time()));
$d2= gmdate("m/d/Y");
$d3=date("m/d/Y");
?>
$d1 always equals $d2 but $d1 may differ from $d3
